Spherical calcium carbonate (CaCO₃) is widely used in industries. However, its large-scale synthesis still remains a challenging issue. Herein, we report the preparation of spherical CaCO₃ at a high calcium hydroxide (Ca(OH)₂) concentration (1.08 M) using CO₂ highly efficiently in methanol (CH₃OH)-water mixed solvent with polyethyleneimine (PEI) as a crystal modifier by carbonation method. Experimental results revealed that the introduction of CH₃OH in the reaction systems decreased the saturation Ca²⁺ concentration in the solvent, and then formed spherical CaCO₃ under the controlled action of PEI. Besides, spherical CaCO₃ with a particle size of about 1 µm can be obtained at concentration of Ca(OH)₂ of 1.08 M, PEI of 5 g/L, and CH₃OH volume content of 30%, stirring rate of 450 rpm, and CO₂ flow rate of 1.4 m³/h. The formation mechanism of spherical CaCO₃ indicated that the particles converted from an initial amorphous precursor, to needle-like, bundle-like, block-like and hemispherical shaped aggregates, and finally to a complete spherical CaCO₃ morphology. This research provides an effective method for the preparation of high yield spherical CaCO₃ by industrial carbonation method.

球形碳酸钙（CaCO ₃）广泛用于工业。然而，其大规模合成仍然是一个具有挑战性的问题。在此，我们报道了在高氢氧化钙 (Ca(OH) ₂ ) 浓度 (1.08 M) 下，使用 CO _{2在甲醇 (CH 3} OH)-水混合溶剂中以聚乙烯亚胺 (PEI)高效制备球形 CaCO ₃碳酸化法晶体改性剂。实验结果表明，反应体系中CH ₃ OH的引入降低了溶剂中的饱和Ca ²⁺浓度，在PEI的控制下形成了球形CaCO _{3 。}此外，球形 CaCO_{在Ca(OH) 2}浓度为1.08 M、PEI为5 g/L、CH ₃ OH体积含量为30%、搅拌速度为450 rpm、CO ₂的条件下，可获得粒径约为1 µm的₃流速为 1.4 m ³ /h。_{球形CaCO 3}的形成机理表明，颗粒由最初的无定形前驱体转变为针状、束状、块状和半球形聚集体，最终形成完整的球形CaCO ₃形态。本研究为工业碳酸化法制备高收率球形CaCO ₃提供了一种有效的方法。